For occasions such as stadiums, lighting equipment is essential for live broadcast or playback of high-speed cameras. When performing slow-motion playback, it is necessary to achieve, for example, 1000 pictures per second without flicker, which requires low current ripple of the dimming circuit of the lighting equipment. And the dimming range of the dimming circuit needs to be wide enough to meet the requirements of different illuminations.
Generally, the conventional method of the dimming circuit is usually to control output feedback voltage or peak current. The former introduces power frequency ripple due to the accuracy of sampling resistance, and the dimming depth cannot be achieved. The latter can achieve lower power frequency ripple of the output current, however, with the depth of dimming, the peak current reference has a large error which makes that the dimming range cannot be wide enough to meet different requirements. Therefore, the existing dimming technology cannot meet the requirements of a wide dimming range and a low output current ripple.
It should be noted that the information disclosed in the background section above is only for enhancing the understanding of the background of the present disclosure, and thus may include information that does not constitute prior art known to those of ordinary skill in the art.